Recently, a new family of Fe-based superconductors has been discovered. Kx Fe2−δSe2 (KFS) is a strongly electron-doped compound with 122-type structure that is characterized by a large Fe magnetic moment and a very high Neel temperature T ￿ 500 K. It has been suggested that this magnetic order coexists with superconductivity below Tc ≈ 30 K, which is an unprecedented situation for superconductivity, as such a strong magnetism would typically lead to its full suppression. Theory predicts an exotic unconventional pairing in these superconductors, which would differentiate them from the s±-pairing in ferropnictides. It was suggested that the gap symmetry is d-wave, which is expected to produce a spin resonance in the magnetic-excitation spectrum near the (π, π) wavevector, in contrast to the (π, 0) resonance in iron arsenides.